ROEWA算法的MATLAB代码

以下是ROEWA算法的MATLAB代码实现：

% 读取SAR图像
I = imread('sar_image.jpg');

% 去噪声
I = medfilt2(I);

% 平滑处理
h = fspecial('gaussian', [5 5], 1);
I = imfilter(I, h);

% 计算一阶导数
[Gx, Gy] = imgradientxy(I, 'sobel');
Gmag = hypot(Gx, Gy);
Gdir = atan2(Gy, Gx);

% 二值化处理
level = graythresh(Gmag);
BW = imbinarize(Gmag, level);

% 形态学操作
SE = strel('disk', 1);
BW = imdilate(BW, SE);
BW = imerode(BW, SE);

% 边缘跟踪
B = bwboundaries(BW);

% ROEWA算法
N = length(B);
for i = 1:N
    boundary = B{i};
    Gmag_boundary = Gmag(sub2ind(size(Gmag), boundary(:,1), boundary(:,2)));
    [~, idx] = sort(Gmag_boundary, 'descend');
    num_seeds = ceil(length(idx) * 0.2);
    seeds = boundary(idx(1:num_seeds),:);
    for j = 1:num_seeds
        seed = seeds(j,:);
        if BW(seed(1), seed(2)) == 0
            continue;
        end
        region = zeros(size(I));
        region(seed(1), seed(2)) = 1;
        while true
            [row, col] = find(region);
            if isempty(row) || length(row) > 100
                break;
            end
            for k = 1:length(row)
                r = row(k);
                c = col(k);
                for m = r-1:r+1
                    for n = c-1:c+1
                        if m < 1 || m > size(I,1) || n < 1 || n > size(I,2) || region(m,n) ~= 0
                            continue;
                        end
                        if abs(Gdir(r,c) - Gdir(m,n)) <= pi/4
                            region(m,n) = 1;
                        end
                    end
                end
            end
        end
        BW(region == 1) = 1;
    end
end

% 绘制边缘
figure, imshow(I);
hold on;
B = bwboundaries(BW);
for i = 1:length(B)
    boundary = B{i};
    plot(boundary(:,2), boundary(:,1), 'r', 'LineWidth', 2);
end

上述代码将SAR图像进行了边缘检测，并使用ROEWA算法进行了边缘优化。需要注意的是，算法中的参数和阈值需要根据具体的图像进行调整。